add ticket purchase page

Co-authored-by: Jan-Marlon Leibl <jleibl@proton.me>
Reviewed-on: http://git.simonis.lol/projects/abiball/pulls/13
Reviewed-by: jank1619 <jan@kjan.email>

config/packages/framework.yaml

@@ -3,7 +3,8 @@ framework:
     secret: '%env(APP_SECRET)%'
 
     # Note that the session will be started ONLY if you read or write from it.
-    session: true
+    session:
+        cookie_samesite: 'lax'
 
     #esi: true
     #fragments: true